JPS635110A - Whirl chamber type combustion chamber of diesel engine - Google Patents

Abstract

PURPOSE:To decrease the flow resistance of combustion air current for avoiding the pressure loss, so as to raise the flaming speed, by forming a recessed part on a piston head, to guide the combustion are current ejected from a nozzle hole, forward, as the leading end part of this recessed part confronts the nozzle hole. CONSTITUTION:A whirl chamber 3 is connected to the eccentric part of a main combustion chamber 1 of a Diesel engine, through a nozzle hole 2. A combustion air current is blown from the nozzle hole 2 against a piston head 8 which is placed near the top dead point. A recessed part 7 adapted to guide the combustion air current ejected from the nozzle hole 2, forward, is formed on the piston head 8, as the shape of this recessed part 7 becomes wider laterally, and shallower, from the leading end part 10 toward the end part 12. The leading end part 10 of the recessed part 7 confronts the nozzle hole 2. In this way, the flow resistance of the combustion air current is decreased, for avoiding the pressure loss, and consequently, the flaming speed can be raised. Moreover, as air-mixing action in the main combustion chamber is accelerated, the air availing rate can be raised.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a whirlpool combustion chamber of a diesel engine, which can effectively improve the air utilization rate even during the period when the piston passes near the top dead center. I will provide a.

Prior Art> As shown in FIG. 3, the basic structure of the whirlpool combustion chamber of a diesel engine, which is the subject of the present invention, is that the whirlpool is connected to an eccentric location of the main combustion chamber 1 of a diesel engine E through a nozzle 2. 3 is connected, and the ring center 4 of the jet nozzle 2 connects the swirl chamber 3 to the main combustion chamber 1.
The combustion airflow is oriented in an inclined manner such that the closer it gets to the center of the main combustion chamber 1, the more the combustion airflow is blown from the nozzle 2 to the piston head 8 located near the top dead center.

Conventional technologies of this type include those in which the jet nozzle 2 is simply formed into a cylindrical shape, and in order to improve the dispersion performance of the combustion air flow in the main combustion chamber 1 and increase the air utilization rate.
As shown in Publication No. 10, a pair of side passages are attached to both wings of a round hole to form a downwardly expanding tapered nozzle 2, and from this nozzle 2 there is a flow of air to the left and right toward a flat piston head that is compressed and raised. There are some that emit a combustion air stream with a widening angle.

<Problems with the prior art> Generally, in order to increase the efficiency of the vortex flow to the thin chamber, it is necessary to make the volume of the thin chamber 3 as large as possible and the main combustion chamber 1 as small as possible. is very narrow.

Therefore, in the above-mentioned conventional technology, the nozzle 2 appears to be blocked by a flat piston head during the period when the piston passes near the top dead center. Even in the case where the combustion airflow expands in the swirl chamber 3, it encounters large flow resistance at the eight nozzle ports 2, causing a pressure loss.

Furthermore, since the combustion airflow is subjected to flow resistance, flame propagation is also delayed, resulting in a decrease in combustion performance.

(Prior Invention) Therefore, the present applicant previously proposed the invention shown in FIG. 6 for the purpose of reducing the flow resistance of the combustion air flow even during the period when the piston passes near the top dead center.

That is, the above-mentioned prior invention forms a sector-shaped recess 7 in the piston head 8 that becomes shallower while expanding laterally from the starting end 10 to the tip 12, and the nozzle 2 has the starting end 10 of the recess 7 open in the swirl chamber 31. This is what I was asked to do.

In the preceding proposal, even during the period when the piston 6 passes near the top dead center, the nozzle 2 is in an open state facing the starting end of the recess 7 formed in the piston head 8, so that the nozzle 2 is connected to the main combustion chamber. The combustion airflow ejected into the recess 7 is smoothly guided toward the tip 1 of the recess 7 without being subjected to flow resistance.

Therefore, while significantly reducing the flow resistance of combustion airflow, reducing pressure loss and eliminating delays in flame propagation,
The combustion airflow that has entered the recess 7 spreads left and right according to the angle between the recesses, but is restrained by the left and right sides 53 of the recess 7, and tries to spread only within this interior. Mixing with air may be restricted.

The technical objective of the present invention is to further improve the air utilization rate in the main combustion chamber.

(Means for Solving the Problems) Means for achieving the above-mentioned problems will be described below with reference to FIGS. 1 to 4, which correspond to embodiments.

That is, in the present invention, when the piston 6 is near the top dead center, the piston has a recess 7 that guides the combustion air flow ejected from the nozzle 2 forward in the main combustion chamber 1 with a spread angle in the left and right direction. The head 8 is formed in a shape that widens left and right and becomes shallower as it progresses from the starting end 10 to the tip 12, so that the starting end 10 of the recess 7 faces the spout 2, and both left and right side surfaces 53 of the recess 7 are formed.
- The feature is that the angle A between the grooves 53 is smaller in the portion 50 near the starting end 10 of the recess 7 and becomes larger in the portion 52 near the tip 12.

Effect> The combustion airflow ejected from the nozzle 2 to the starting part 10 of the recess 7 has no directionality in the part 50 near the starting end 101 while being restrained by the left and right side surfaces 53 and S3 set at a narrow angle. The left and right side surfaces 53 and 53 are attached to each other and move towards the tip 12, but in the portion 52 near the tip 12, the left and right side surfaces 53, 53 are set at a wide angle.
As a result, the restriction on spreading to the left and right is released, so that it can expand greatly to the left and right, and can smoothly wrap around the cylinder peripheral wall by dividing into two parts.

<Effects of the Invention> First, in the present invention, by forming a recess in the piston head, the flow resistance of the combustion air flow is reduced, pressure loss is eliminated, and flame propagation can be quickly achieved.

Furthermore, at the tip of the recess, the combustion airflow widely spreads left and right and can smoothly wrap around the sill peripheral wall, promoting mixing with the air in the main combustion chamber and improving air utilization.

Practical example Embodiments of the present invention will be described below with reference to the drawings.

Fig. 1 is a plan view of the piston head showing the first embodiment, Fig. 2 is a vertical right side view of the vicinity of the piston head, Fig. 3 is a longitudinal right side view of the main part of a vertical diesel engine, and Fig. 10 is a vertical right side view of the main part of the vertical diesel engine. This is a schematic diagram, and a cylinder 15 is formed in the center of a cylinder block 14 of a diesel engine E, and a piston 6 is fitted into the cylinder 15 so as to be vertically slidable.

The cylinder head 16 is assembled above the cylinder block 14, and one fuel injection space is bored in the wall facing the main combustion chamber 1 of the cylinder block 14 in the rear half of the cylinder head 16, and the lower opening end of the cylinder head 16 is assembled. The half-shaped injection chamber member 20 is fitted from the edge, and the upper hemisphere of the fuel injection space 19 and the lower hemisphere of the injection chamber member 20 form a thin chamber 3.

A nozzle fitting hole 21 is provided extending from the upper end of the rear half of the cylinder head 16 to the fuel injection space 19. A fuel injection nozzle 22 is fitted into the fitting hole 21, and its tip nozzle 23 is inserted into the swirl chamber. 3, the nozzle 2 is placed in the above-mentioned injection chamber member 20.
In other words, the ring center 4 of the jet nozzle 2 is oriented in an inclined manner such that as it approaches the main combustion chamber 1 from the vortex chamber 3, it approaches the central part of the main combustion chamber 1 by one inch.

As shown in FIG. 10, the nozzle 2 has a round hole 24 in the center that serves as the main jetting path for the combustion air flow, and has side passages 25 on both left and right sides 5 slightly forward of the hole. It is constructed with a mountain-shaped boundary.

Move each wheel center of the side passage 25 downward with respect to the wheel center of the round hole 24 (
It is tilted so that it expands to the left and right (i.e., the side street 25
The cross-sectional area of the passage is configured to increase in the left-right direction as it approaches the main combustion chamber 1), so that the combustion air jetted from the nozzle 2' into the main combustion chamber 1 spreads in both left and right directions.

In addition to the above-mentioned embodiments, the tapered nozzle 2 that spreads the combustion air flow laterally may also have elongated holes on both the upper and lower surfaces of the nozzle, as shown in FIG. 11. However, in the present invention, a simply cylindrical nozzle 2 as shown in FIG. 12 may also be used.

- On the other hand, the piston head 8 is provided with a ginkgo leaf-shaped recess 7 that opens at approximately 60 degrees, and the recess is formed such that the recess is deepest at the starting end 10, which is the key part of the ginkgo leaf, and becomes shallower as it advances toward the tip end 12. (See Figure 1).

The recess 7 is arranged near the center of the main combustion chamber head 8, and its starting end GLO faces the opening end of the jet nozzle 2 on the main combustion chamber side.

As described above, the shape of the recess 7 in plan view is approximately a ginkgo leaf shape, and specifically, between the left and right sides 53, 53, the middle part from the starting end 10 to the tip end 12 is formed into a small shape. The gap angle A1 is set, and the left and right sides 53 and 53 from the middle part to the tip 12 are set so that the gap A2 is larger than the above A1 and gradually increases as it approaches the tip 12 (therefore, the starting edge Part 50 of both left and right wall surfaces near part 40
has a linear shape, and the portions 5 on both the left and right walls near the tip 12
2 exhibits a curved shape).

Further, the shape of the recess 7 in the longitudinal direction is such that the starting end 10 is bored into a spherical shape, and the area from the starting end 10 to the tip 12 is an upwardly sloping flat surface, so that the spherical surface and the flat surface are smoothly connected. It is something that

At this time, the combustion airflow ejected from the nozzle 2 to the starting end 10 of the recess 7 is directed at the side wall portion 50 near the starting point 1111FIs10, advances to the middle part, and widens the angle at the side wall portion 52 near the tip 12. It rotates and expands left and right,
Improve air utilization.

Ikegata, FIG. 4 shows a second embodiment of the present invention, in which a portion 52 from the middle of the left and right side walls 53, 53 to the tip 12 is shown in FIG.
is set at an interval angle A2 larger than the interval angle A1 in the vicinity of the starting end 50, and is expanded in a curved shape in the first embodiment, whereas in this embodiment, it is expanded in a straight line.

Moreover, since the recess 7 may have a shape that becomes shallower as it progresses from the starting end 10 to the tip end 12, the shape in the longitudinal direction is not limited to the above embodiment, and may be as follows.

That is, FIG. 6 shows a first modification of the recess 7 in the longitudinal direction,
The starting end 10 is cut down into a flat surface 30 that slopes upward at the rear, the part from the starting end 10 to the middle part of the recess is a flat face 31 of the same depth, and the part from the middle part to the tip 12 is recessed downward. The single curved surface 32 (having a radius of curvature in the front-rear direction) is formed by smoothly continuing the single curved surface 32 to the flat surface 31 described above.

FIG. 7 shows a second modification example of the longitudinal direction of the recess 7, in which the lowering start portion of the starting end 10 of the first embodiment is formed into a curved shape, so that the recess 7 and the upper wall surface of the screw head 6 are connected to each other. are connected by a smooth continuous surface, eliminating the formation of sharp corners at the starting end and preventing the occurrence of cracks and heat points.

FIG. 8 shows a third modification in the longitudinal direction of the recess 7, in which in the first modification, the part from the middle part of the recess to the tip 12 is formed into a flat surface 34 with a front curved slope. , the central and rear flat surfaces are connected in the form of a line.

FIG. 9 shows a fourth modification of the longitudinal direction of the recess 7, in which the starting portion 10 of the first embodiment is lowered into a vertical flat surface.

[Brief explanation of drawings]

1 to 4 show embodiments of the present invention, and FIG. 1 is a first embodiment of the present invention.
FIG. 2 is a vertical right side view of the vicinity of the piston head, FIG. 3 is a vertical right side view of main parts of a vertical diesel engine, and FIG. 4 is a first side view of the piston head showing the second embodiment. FIG. 5 is a view equivalent to FIG. 1 showing the prior invention, FIGS. 6 to 9 are longitudinal right side views of main parts of the piston head V showing modifications in the longitudinal direction of the recesses, and FIG. The figure is a schematic diagram of the spout, and Figures 11 and 12 are views corresponding to Figure 10 showing modified examples of the pond at the spout. DESCRIPTION OF SYMBOLS 1... Main combustion chamber, 2... Jet nozzle, 3... Whirlpool chamber, 4... Wheel center, 6... Piston, 7...
・Dents, buttholes, piston head, 10...7 i
i part, end part of 12...7, 10 of 50...7
The part close to , 52...The part close to 12 of 7, 53.
...Left and right sides of 7, A...Angle between 53, E...
diesel engine.

Claims (1)

[Claims] 1. A whirlpool chamber 3 is connected to an eccentric point of the main combustion chamber 1 of a diesel engine E through a nozzle 2, and the ring center 4 of the nozzle 2 approaches the center of the main combustion chamber 1 from the whirlpool chamber 3 toward the main combustion chamber 1. In a diesel engine whirlpool combustion chamber configured to blow combustion air from the nozzle 2 to the piston head 8 near the top dead center, when the piston 6 is near the top dead center. , a concavity 7 is provided in the piston head 8 for guiding the combustion air flow ejected from the nozzle 2 forward in the main combustion chamber 1 with a spread angle in the left and right directions, and the recess 7 is formed in the piston head 8 and spreads left and right as it advances from the starting end 10 to the tip end 12. The starting end 10 of the recess 7 is made to face the nozzle 2, and the angle A between the left and right sides 53 and 53 of the recess 7 is small at the part 50 near the starting end 10 of the recess 7, and the tip A swirl chamber type combustion chamber of a diesel engine characterized in that a portion 52 close to 12 has a large value.